Happy 2017 Year and annual summary of xDevs.com projects

Not so long ago we were happy to report annual progress of year 2015, and now it’s time for same once again. There was much more work behind the scenes and few off-line IRL events, covered to some extent in xDevs.com articles. xDevs.com site was created and published in 2008, and continue to be 100% ad-free experimental project to support engineers and share the electronics engineering knowledge. It was not always easy, nor cheap to have new content and projects, but we still here around.

After few months of work to get multilingual interface and support on our site, it revealed high requirements for maintenance. As a result, decision to provide more frequent new content to core English-speaking audience multiple language interface was reverted back to English-only. It will likely to stay this way in 2017 year.

  • Started development on universal calibration software to automate gear maintenance/performance report generation.
  • New project started, which remain to be secret for now…
  • Many new articles, reviews and repairs were performed and uploaded

New content on site

Full list of all new articles in 2016:

Tale 1 : Little jumper, or sharks in voltage references world Articles
Tale 2 : Calibration festival concept Articles
Fluke 5700A calibrator review and service Repair
Standalone using Fluke 5700A REF-DAC module Articles
Fluke 720A Kelvin-Varley Divider restoration Repair
Tweaks and mods for HP 3457A 6.5-digit DMM Articles
Review of Tektronix MDO4000C mixed domain oscilloscope Review
Repair and PC HW ugrades for TDS5000B series scope Repair
DCV calibration program for DIY volt-nuts with our KX LTZ1000 module Articles
Repair log of reader’s HP 3458A precision DMM Repair
Repair of second HP 3458A metrology DMM Repair
Review of Keithley 2001-TCSCAN scanner card for 200x DMMs with CJC Review
Linear DC907A-A Current sense demoboard test Review
Impementation of USB DFU secondary bootloader for NXP LPC11U68 MCU Guides
Teardown of Keithley Model 3706A switch/scan DMM Review
Test and review of Linear LTC1668 50MSPS 16-bit DAC demo board Review
Using ALTERA/Terasic DE1-SoC (Cyclone V SE FPGA SoC) kit for linux-gpib Guides
Setting up and using Agilent 82357B GPIB USB pod in RPi Linux Guides
Wavetek 4920M AC Voltmeter Standard restoration Repair
Ultra-quiet LDO module design, based on Linear LT3042 Articles
HP 4262A LCR meter restoration and testing Repair
HP 8753A Network Analyzer repair project – in progress Repair
Data Proof DP160 low thermal EMF scanner teardown Review
Repair of ALTERA SMB2 FPGA development board Repair
Reader contribution: Datron 4800 MFC PCB photos News
Review and application of EM A10 nanovolt amplifier Review
International SI volt transfer experiment Articles
Extreme OC modifications for EVGA GeForce GTX 1080/1070 FE Guides
Repair and use of old 19 inch TFT LCD monitor Articles
How to recover white color of old plastic panels and buttons Guides
Review of Raspberry Pi 3 and setting up for GPIB/lab use Review
How to remove ads in Skype Guides
xDevs.com development mini-modules Articles
DIY Calibration resistance box build Articles
Tesla MAB399 and MAC01 voltage references review and teardown Review
Agilent 4142B semiconductor SMU system repair and usage Repair
Datron 4910 series DC voltage reference repair Repair
Time Electronics 9823 AC-DC calibrator repair Repair
RF connectors types and cables Guides
Repair and tweaks for Fluke 845AB null-meter Repair
Keithley Model 2304A high-speed PSU repair worklog Repair
Keithley Model 7172 Low current 8×12 Matrix card review Review
Keithley Model 2002 repair Repair
Keithley 262 low thermal divider overhaul Repair
Keithley 6514 Electrometer repair Repair
Design of low-noise power supply for DIY precision standard Articles
Using LCD and OLED with Raspberry Pi and python Guides
Testing of Fluke 720A KVD resistors Articles
Review of old modules TLA7M3 and TLA7N3 for TLA700-series LA’s Review
Keithley 2182 nV voltmeter repair worklog Repair
Datron 1281 DMM repair and calibration worklog Repair
HP 34401A repair and calibration worklog Repair
LCD font generation with font examples Articles
Using BME280 temperature/humidity/pressure sensor with Raspberry Pi Guides
Repair and review of Guildline 9330 standard resistor Repair
Adding SPI/I2C protocol decoder to Tektronix TLA700/7000 series LA Guides
Nikkor AF-S 28-70/2.8 lens repair Repair
TEMEX Rubidium frequency standard repair and Trimble GPSDO test Repair

That’s total 58 articles added, with few more still in works. If you interested in metrology and ultra-high performance equipment voodoo, be sure to check our Fluke 5700A calibrator review and service and it’s DAC A11 PCBA, Agilent 4142B worklog, interesting 8½-digit Datron 1281 DMM repair worklog.

Few more tests were done on our own xDevs.com KX LTZ1000-based references, covered in Tale 1.

Appreciate support from community and especially from new author, Todd. We already have lot of plans for 2017 to do even more content. It definitely helps, keeping this hobby going to have active discussion on such niche engineering areas. Also Dave L. Jones aka “EEVBlog” created new metrology section on his engineering forum, so many very interesting discussions happen over there. Take a minute and check it out.

Offline events and our own calibration setup.

After a succesful HP 3458A repair big question was revealed how to maintain and keep it’s great specification for use in future projects and repairs.

Since I’ve already got few of best references money can buy, in form of LTZ1000 KX-REF modules it was logical step to use bank of them as DCV transfer standards. For resistance and current multiple stable VPG BMF resistors, with tempco specified ±2ppm/max used. As 3458A allows full calibration with just 7-10 V DC reference and 10 KOmega; resistance standard it’s now a secondary standard for our use.

Few events were established to transfer references and obtain accurate DCV and OHM measurements.

Calibration fest in August 2016, held in USA

It was a one week long event, with next achieved results:

  • Fluke 5700A/03 MFC was calibrated to Fluke 732B 10 V, SR104 10KΩ and IET 1 Ω references. All references calibrated under 6 days by accredited labs with sub-ppm accuracy.
  • Transfer HP 3458A-002 calibrated same time.
  • Keithley 2002 #1 was calibrated to F5700/3458A-002
  • Keithley 2002 #2 was calibrated to F5700/3458A-002
  • Bank of our xDevs.com KX LTZ1000 references and resistance standard box were calibrated
  • Keithley 6514A fixed as side-effect result

Both Keithley 2002’s travelled back with me to Taiwan in checked in luggage without single issue. Test after warm-up revealed same 1 ppm offset between meter, recorded as reference during Cal-Fest event. This allowed to obtain absolute accuracy with ±1ppm for 1-10 VDC ranges and ±2.4 ppm for 1-100 KΩ resistance ranges. Plan for 2017 is to extend accuracy also for current and alternating voltage.

Calibration meetup in November 2016, held in Taiwan

This event was much shorter, just a weekend meet-up in sunny city Taichung. I’ve brought back HP 3458A from owner and took our Wavetek 4920 for a ride.

  • Fixed HP 3458A was hand-carried to happy owner
  • Fluke 5700A tested using self-check
  • Fluke 5720A tested using self-check
  • Wavetek 4920M was calibrated to Fluke 5790A with 5720A as source.

Our 4920M travel back to homelab with completed user’s and factory low level calibrations, except the wideband input (none of Flukes had WB option). This brings 4920M as initial reference for ACV from 100 mV to 1000 V with frequency up to 1 MHz.


During 2016 our website visited 19604 users, with over 7.1M page views. There is no target to capture most views/clicks, no staff involved in full-time project development, so I reveal these numbers just for curious minds. Focus is still to keep high SNR-level on specific niche content we publish, instead going all about broad-topic talks for wider audience. Main focus this year was on high-end test and electrical calibration equipment, such as voltage standards, multi-function calibrators and long scale DMMs.

There are still lot of things to do and improve, so looking forward to next year progress and contributions, targeting to provide even better quality content. Key focus area next year is to work on our own project designs and cowork with other hobbyists, with much more valuable how-to’s and content to be published online! Contact me directly if you have any questions. Every comment matters ;)

We hope to have more advanced experiments, teardowns, repairs and videos in new year. If you wish to publish your findings, articles or lab notes, we are happy to do so. xDevs.com will fund each publication at fixed rate. Details about this will be public soon. Stay tuned!

Happy New 2017!

Ilya Tsemenko
xDevs.com Project

Author: xDevs.com Team
Created: Dec. 28, 2016, 2:48 a.m.
Modified: Jan. 4, 2017, 5:35 a.m.